To be permitted by your girlfriend/spouse to indulge in such activities that are normally banned in her absence.
Activities include visiting a drinking establishment with your mates, going clubbing and generally entertaining yourself in the presence of other males and/or females without being constantly reminded of your social obligations towards her.
In a broader sense, these activities include pretty much everything that is fun and does not revolve around her.
Pink tickets generally tend to apply to evening activities and are always of a fixed duration (usually no longer than a few hours).
The applicant must often state and commit to a pre-agreed expiration time, upon which he must return to her custody.
"I've got a pink ticket tonight. Let's get sloshed
"John didn't get a pink ticket. I guess it's just us going MILF